Photographic processes



United States Patent 3,196,014 PHOTOGRAPHHC PRUCESSES Howard G. Rogers, Weston, Mass, assignor to Polaroid Corporation, (Zambridge, Mass, a corporation of Delaware No Drawing. Filed Jan. 25, 1959, $21. No. 788,742 The portion of the term of the patent subsequent to Mar. 12, 1980, has been disclaimed 8 Claims. (Cl. tie-29) This invention relates to photography and, more particularly, to improvement in photographic diffusion-transfer reveral processes for obtaining color images.

This application is a continuation-in-part of my copending US. application Serial No. 734,860, filed May 13, 1958.

A principal object of the present invention is to provide novel processes wherein developing agents capable of developing a latent image and imparting a reversed or positive colored image of said latent image to a superposed image-receiving material are stabilized subsequent to formation of said positive colored image.

Another object is to provide novel processes suitable for use in preparing stabilized monochromatic and multichromatic photographic images.

A further object is to increase the stability of positive diffusion-transfer reversal colored images against the deleterious effects of actinic radiation.

A still further object is to increase the stability of positive diffusion-transfer reversal colored images against the deleterious effects of high humidity and/or high temperatures.

A still further object is to stabilize transferred dye developer in a difiusion-transfer reversal image-receiving element by complexing said dye developer with an appropriate metal.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the processes involving the several steps and the relation and order of one or more of such steps with respect to each of the other, and the products possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

My copending application erial No. 748,421, filed July 14, 1958, a continuation-in-part of Serial No. 415,073, filed March 9, 1954 (now abandoned), discloses diffusiontransfer reversal processes wherein a photographic negative material, such as a photographic element comprising an exposed silver halide emulsion layer containing a latent image, is processed using a dye developer to impart to an image-receiving element a reversed or positive dye image of said latent image by permeating into said emulsion layer a suitable liquid processing composition and bringing said emulsion layer into superposed relationship with an appropriate image-receiving layer.

In carrying out the processes of this invention, a photosensitive element containing a silver halide emulsion is exposed and wetted with a liquid processing composition, for example, by immersing, coating, spraying, flowing, etc., in the dark, and the photosensitive element superposed, prior to, during or after wetting, on a sheet-like support element, which may be utilized as an imagereceiving element. In a preferred embodiment, the photosensitive element contains a layer of dye developer, and the liquid processing composition is applied to the photosensitive element in a uniform layer as the photosensitive element is brought into superposed position with an imagereceiving element. It is also within the scope of this invention to apply the liquid processing composition prior to exposure, in accordance with the disclosure in the cosodium carboxymethyl cellulose.

pending application of Edwin H. Land, Serial No. 498,672, filed April 1, 1955. The liquid processing composition permeates the emulsion to provide a solution of dye developer substantially uniformly distributed therein. As the latent image is developed, the oxidation product of the dye developer is immobilized or precipitated in situ with the developed silver, thereby providing an imagewise distribution of unoxidized dye developer dissolved in the liquid processing composition. This immobilization is apparently, at least in part, due to a change in the solubility characteristics of the dye developer upon oxidation, and especially as regards its solubility in alkaline solutions. It may also be due, in part, to a tanning effect on the emulsion by the oxidized developing agent. At least part of this imagewise distribution of unoxidized dye developer is transferred, by imbibition, to a superposed image-receiving layer or element, said transfer substantially excluding silver or oxidized dye developer. The latter element receives a depthwise diffusion, from the emulsion, of unoxidized mobile dye developer without appreciably disturbing the imagewise distribution thereof to provide a reversed or positive, colored image of the developed image. If the color of the diffused dye developer is affected by changes in the pH of the image-receiving element, this pH may be adjusted in accordance with well-known techniques to provide a pH affording the desired color. Imbibition periods of approximately one minute have been found to give good results, but this contact period may be adjusted where necessary to compensate for variations in temperature or other conditions. The desired positive image is revealed by stripping the image-receiving element from the photosensitive element at the end of the imbibition period.

The aforementioned dye developers may be utilized in the photosensitive element, for example in, on or behind the silver halide emulsion, or they may be utilized in the image-receiving element or in the liquid processing composition. In a preferred embodiment, a coating or layer of the dye developer is placed behind the silver halide emulsion, i.e., on the side of the emulsion adapted to be located most distant from the photographed subject when the emulsion is exposed and preferably also adapted to be most distant from the image-receiving element when in superposed relationship therewith. Placing the dye developer behind the emulsion layer, as in the preferred embodiment, has the advantage of providing increased contrast in the positive image, and also minimizes any light-filtering action by the colored dye developer. In this preferred embodiment, the layer of dye developer may be applied by using a coating solution containing about 0.5 to 8% by weight, of the dye developer. Similar concentrations may be used if the dye developer is utilized as a component of the liquid processing composition, concentrations as low as 0.2% in the liquid processing composition being suitable in certain instances.

The liquid processing composition above referred to comprises at least an aqueous solution of an alkaline compound, for example diethylamine, sodium hydroxide or sodiuin carbonate, and may contain the dye developer. In some instances, it may contain a minor amount of a conventional developing agent. If the liquid processing composition is to beapplied to the emulsion by being spread thereon, preferably in a relatively thin, uniform layer, it may also include a viscosity-increasing compound constituting the film-forming material of the type which, when said composition is spread and dried, will form a relatively firm and relatively stable film. A preferred film-forming material is a high molecular weight polymer such as a polymeric, water-soluble ether inert to an alkali solution as, for example, a hydroxyethyl cellulose or materials or thickening agents whose ability to increase Other film-forming sneaora 2 0- o i V N=N- wherein R is an alkyl or hydroxyl group; by means of which a chelate ring may be formed, for example, between an azo, hydroxyl or carboxyl group and a metal atom covalently attached to the oxygen atom of a phenolic or enolic hydroxyl group.

. In general, the aforementioned complexing may be accomplished as a result of contacting the appropriate dye developer with a chelating metal, preferably a metallic ion derived from an ionizable salt or a chelate exhibiting less stability than the dye developer chelate ultimately desired, subsequent to transfer of the image-forming dye developer to a superposed image-receiving element. The contact may be accomplished by any of the varied procedures known to the photographic art, for example, in diffusion-transfer reversal processes, the metallic salt and/ or chelate may be dispersed within and/or disposed in a separate layer superposed on the respective imagereceiving elements such that transferred dye developer contacts said metallic salt and/or chelate on and/or within said receiving layer to form the desired complex thereon and/ or therein. The metallic salt and/ or chelate may also be disposed in an appropriate processing solution, for example where desirable, the image-receiving element may be contacted with a solution of the metallic salt and/or chelate subsequent to formation of the desired image as Well as subsequent to displacement of the image-receiving element from its superposed relation to a photosensitive negative element.

It is to be understood that the process utilized may comprise in whole or in part one or more of the previously enumerated procedures to suit the requirements of the operator.

Economy of manufacture, simplified processing and the inherent desirability of utilizing a single-step photographic prooess, in regard to processing, time, equipment and chemicals, have determined that dispersing the metal, preferably in the aforementioned ionizable salt and/or chelate form, in an image-receiving element is the preferred procedurefor carrying out the processes of the present invention.

It should be noted that it is within the scope of this invention to form images which comprise mixtures of complexed and uncomplexed dye developers and to effect complexing either at roomtemperature or at an artificially designated temperature, as for example, complexing at elevated temperatures.

According to one embodiment of the present invention, monoand disazo-dye developers containing hydroxyl and/ or carboxyl radicals substituted, respectively, on aryl nuclei at positions ortho and ortho to at least one azo linkage form stable coordination complexes as a result of contacting the appropriate dye developer with a nickel, copper, cobalt, etc., ionizable salt and/or chelate, for example, a nitrate, sulfate, oxalate, etc., salt and/or a chelate of the formula:

' from the group consisting of aliphatic and aromatic groups; X and Y each may be the same or different and are selected from the group consisting of -O and :NOH groups; and Z is a metallic atom selected from the group consisting of copper and nickel; for example a nickel or copper chelate of an enolizable fl-diketone, such as acetylacetone, an enolizable li-keto ester, such as ethyl acetoacetate, an enolizable S-ketoxime, such as dibenzoylmethane monoxime, or a fi-ketoaldehyde; subsesuent to transfer of the imageforming dye developers to P a superposed image-receiving element.

The last-mentioned embodiment of the present invention will be illustrated in greater detail in conjunction with the following specific examples which set out representative utilizations of this embodiment which, however, are not limited to the details therein set forth and are intended to be illustrative only. In the following examples all parts are given by weight except where otherwise noted, and all operations involving light-sensitive materials are carried out in the absence of actinic radiation.

Example 1 Two monocrome photographic prints are prepared according to the following procedure.

A photosensitive element is prepared by coating a gelatin-coated film base with a solution containing 4% of 2- hydroxynaphthalene--azohydroquinone, which is disclosed in the copending U.S. application of Elkan R. Blout, Saul G. Cohen, Milton Green, and Myron S. Simon, Serial No. 775,804, filed August 18, 1958, a continuattionin-part of application Serial No. 450,208, filed August 16, 1954, me 4% solution of cellulose acetate hydrogen phthalate in a 50:50 mixture, by volume, of acetone and tetrahydrofuran. After this coating has dried, a silver iodobromide emulsion is applied. This photosensitive element is exposed and processed by spreading an aqueous liquid processing composition comprising:

- Percent Sodium carboxymethyl cellulose 3.5

1-phenyl-3-pyrazolidone 0.1

Sodium hydroxide 2.0

2,5-bis-ethyleneiminohydroquinone 0.3

6 -nitrobenzimidazole 0.24

minute, the image-receiving element is separated and contains a magenta dye image of the photographed subject.

Example 2 One of the monochrome prints prepared in Example 1 is exposed to a 275 watt sunlamp at a distance of ca. 20 inches for 72 hours.

Optical density measurements of the dye image subsequent to this accelerated ageing test showed a loss of density, e.g., from a density of 2.30 to a density of 1.05.

Example 3 Density prior Density to exposure subsequent to exposure Example 4 A monochrome print is prepared according to the following procedure.

A photosensitive element is prepared according to the procedure stated in Example 1. This photosensitive element is exposed and processed by spreading the liquid processing composition of Example 1 between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element comprises a cellulose acetatecoated baryta paper which has been coated with a solution comprising 1% copper sulfate and 4% N-methoxymethyl polyhexarnethylene adipamide in 80% aqueous isopropanol. After an imbibition period of approximately one minute, the image-receiving element is separated and contains a purple dye image of the photographed subject.

The resultant print is exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

Optical density measurements of the exposure effect on the copper-complexed dye image at several positions on the print, exhibits the following results:

Density prior Density to exposure subsequent to exposure Example 5 is applied. This photosensitive emulsion is exposed and processed according to the procedure of Example 1. After an imbibition period of approximately one minute, the image-receiving element is separated and contains an orange-red dye image of the photographed subject.

Example 6 One of the monochrome prints prepared in Example 5 is exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

Optical density measurements of the dye image after the accelerated ageing exposure showed considerable fading had occurred.

Example 7 The second of the monochrome prints prepared in Example 5 is swabbed with a 1% solution of copper sulfate in a methanol-water solvent to form a copper-complexed magenta dye image of the photographed subject and exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

Optical density measurements of the exposure effect on the copper-complexed dye image at several positions on the print exhibits the following results:

Density prior Density to exposure subsequent to exposure Example 8 A monochrome print is prepared according to the following procedure.

A photosensitive element is prepared according to the procedure stated in Example 5. This photosensitive element is exposed and processed by spreading the liquid processing composition of Example 1 between said photosensitive element and an image-receiving element prepared according to the procedure stated in Example 4. After an imbibition period of approximately one minute, the image-receiving element is separated and contains a magenta dye image of the photographed subject.

The resultant print is exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

Optical density measurements of the exposure effect on the copper-complexed dye image at several positions on the print exhibits the folowing results:

Density prior Density to exposure subsequent to exposure Example 9 Example 10 A monochrome print is prepared according to the following procedure.

' A photosensitive element is prepared according to the procedure stated in Example 1. This photosensitive element is exposed and processed by spreading the liquid processing composition of Example 1 between saidphotosensitive element and an image-receiving element as said elements are brought into superposed relationship. The

image-receiving element comprises a cellulose acetatecoated baryta paper which has been coated with a solution comprising approximately 0.5% of bis-(acetylacetono) copper (II) and 4% N-methoxymethyl polyhexamethylene adipamide in 80% aqueous isopropanol. After an imbibition period of approximately one minute, the image-receiving element is separated and contains a coppcr-complexed reversed positive dye image of the photographed subject. A

The resultant print, containing the complexed dye image of the photographed subject, exhibits an initial density substantially equivalent to the noncomplexed dye images of Example 1 and is exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

The copper-complexed dye image exhibits substantially no degradation due to the heat and actinic radiation of the aforementioned procedure.

Example 11 A monohcrome print is prepared according to the procedure stated in Example 1. v

The resultant print, containing a magenta dye image of the photographed subject, is swabbed with an approximately 0.5% solution of bis(ethylacetoacetato) copper (II) in a 50:50 solution, by volume, of water and methanol and exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

The copper-complexed' dye image exhibits substantially no degradation due to the heat and actinic radiation of the aforementioned procedure.

Example 12 A monochrome print is prepared according to the following procedure.

A photosensitive element is prepared according to the procedure stated in Example 1. This photosensitive element is exposed and processed by spreading the liquid processing composition of Example 1 between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element comprises a cellulose acetatecoated baryta paper which has been coated with a solution comprising approximately 0.5% of bis-(ethylacetoacetato) copper (II) and 4% N-methoxymethyl polyhexamethylene adipamide in 80% aqueous isopropanol. After an imbibition period of approximately one minute, the image-receiving element is separated and contains a copper-complexed reversed positive dye image of the photographed subject.

The resultant print, containing the complexed dye image of the photographed subject, exhibits an initial density substantially equivalent to the noncomplexed dye images of Example 1 and is exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

The copper-complexed dye image exhibits substantially no degradation due to the heat and actinic radiation of the aforementioned procedure.

Example 13 A monochrome print is prepared according to the following procedure.

A photosensitive element is prepared according to the procedure stated in Example 5. This photosensitive element is exposed and processed by spreading the liquid processing composition of Example 1 between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship, The

image-receiving element comprises a cellulose acetatecoated baryta paper which has been coated with a solution comprising approximately 0.5% of bis-(ethylacetoacetato) copper (i1) and 4% N-methoxymethyl polyhexamethylene adipamide in aqueous isopropanol. After an imbibition period of approximately one minute, the image-receiving element is separated and contains a copper-complexed reversed positive dye image of the photographed subject.

The resultant print, containing the complexed dye image of the photographed subject, exhibits an initial density substantially equivalent to the noncomplexed dye images of Example 5 and is exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

The copper-complexed dye image exhibits substantially no degradation due to the heat and actinic radiation of the aforementioned procedure.

Example 14 A monochrome print is prepared according to the procedure stated in Example 1.

The resultant print, containing a magenta dye image of the photographed subject, is swabbed with an approximately 0.5% solution of bis-(trifluoroacetylacetono) copper (II) in a 50:50 solution, by volume, of water and methanol and exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

The purple copper-complexed dye image exhibits substantially no degradation due to the heat and actinic radiation of the aforementioned procedure.

Example 15 A monochrome print is prepared according to the following procedure.

A photosensitive element is prepared according to the procedure stated in Example 1. This photosensitive element is exposed and processed by spreading the liquid processing composition of Example 1 between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element comprises a cellulose acetatecoated baryta paper which has been coated with a solution comprising approximately 0.5 of bis-(trifluoroacetylacetono) copper (II) and 4% N-methoxymethyl polyhexamethylene adipamide in 80% aqueous isopropanol. After an imbibition period of approximately one minute, the image-receiving element is separated and contains a copper-complexed reversed positive purple dye image of the photographed subject.

The resultant print, containing the complexed dye image of the photographed subject, exhibits an initial density substantially equivalent to the noncomplexed dye images of Example 1 and is exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

The copper-complexed dye image exhibits substantially no degradation due to the heat and actinic radiation of the aforementioned procedure.

Example 16 A monochrome print is prepared according to the following procedure.

A photosensitive element is prepared according to the procedure stated in Example 1. This photosensitive element is exposed and processed by spreading the liquid processing composition of Example 1 between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element comprises a cellulose acetatecoated baryta paper which has been coated with a solution comprising approximately 0.5% of bis-(salicylaldoximo) copper (II) and 4% N-methoxymethyl polyhexamethylene adipamide in 80% aqueous isopropanol. After an imbibition period of approximately one minute, the image-receiving element is separated and contains a copper-complexed reversed positive dye image of the photographed subject.

The resultant print, containing the complexed dye image of the photographed subject, exhibits increased stability against the degradation efiects of exposure to the heat and actinic radiation of the accelerated ageing test procedure disclosed in Example 2.

Example 18 A monochrome print is prepared according to the procedure stated in Example 1.

The resultant print, containing a magenta dye image of the photographed subject, is swabbcd with an approximately 0.5% solution of bis-(ethylacetoacetato) nickel (II) in a water-methanol solvent and exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

The nickel-complexed dye image exhibits increased stability against the degradation effects of exposure to the heat and actinic radiation of the aforementioned procedure.

Example 19 A monochrome print is prepared according to the following procedure.

A photosensitive element is prepared according to the procedure stated in Example 1. This photosensitive element is exposed and processed by spreading the liquid processing composition of Example 1 between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element comprises a cellulose acetatecoated baryta paper which has been coated with a solution comprising approximately 0.5% of bis-(ethylacetoacetato) nickel (E) and 4% N-methoxymethyl polyhexamethylene adipamide in 80% aqueous isopropanol. After an imbibition period of approximately one minute, the image-receiving element is separated and contains a n-ickel-complexed reversed positive dye image of the photographed subject.

The resultant print, containing the complexed dye image of the photographed subject, exhibits increased stability against the degradation eiiects of exposure to the heat and actinic radiation of the accelerated ageing test procedure disclosed in Example 2.

Example 20 A monochrome print is prepared according to the procedure stated in Example 1.

The resultant print, containing a magenta dye image of the photographed subject, is swabbed with an approximately 0.5% solution of bis-(acetylacetono) nickel (H) in a water-methanol solvent and exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

The nickel-complexed dye image exhibits increased stability against the degradation effects of exposure to the heat and actinic radiation of the aforementioned procedure.

Example 21 A monochrome print is prepared according to the following procedure.

A photosensitive element is prepared according to the procedure stated in Example 1. This photosensitive element is exposed and processed by spreading the liquid processing composition of Example 1 between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The imagea'eceiving element comprises a cellulose acetatecoated baryta paper which has been coated with a solution comprising approximately 0.5% of bis-(acetylacetono) nickel (II) and 4% N-methoxymethyl polyhexamethylene adipamide in aqueous isopropanol. After an imbibition period of approximately one minute, the image-receiving element is separated and contains a nickel-complexed reversed positive dye image of the photographed subject.

The resultant print, containing the complexed dye image of the photographed subject, exhibits increased stability against the degradation effects of exposure to the heat and actinic radiation of the accelerated ageing test procedure disclosed in Example 2.

Example 22 Two monochrome photographic prints are prepared according to the following procedure.

The photosensitive element is prepared by coating a gelatin-coated film base with a solution containing 3% of 4 acetyl 2 (4-[5-(hydroquinonyl)-ethyl]-2'-hydroxyphenylazo)-1-naphthol, which is disclosed in the aforementioned copending US. application Serial No. 788,893, in a 2% solution of cellulose acetate hydrogen phthalate in a 50:50 mixture, by volume, of acetone and tetrahydrofuran. After this coating has dried, a silver iodobromide emulsion is applied. This photosensitive emulsion is exposed and processed according to the procedure of Examie '1 vvith an aqueous liquid processing composition comprising:

Percent Sodium carboxymethyl cellulose 4.5 l-phenyl-3-pyrazolidone 0.6 Sodium hydroxide 2.0 2,5-bis-ethyleneiminohydroquinone 0.4 6-nitr0benzimidazole 0.12

After an imbibition period of approximately one minute, the image-receiving element is separated and contains an orange-red dye image of the photographed subject.

Example 23 One of the monochrome prints prepared in Example 22 is exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

Examination of the print after the accelerated fading test showed that substantial fading had occurred.

Example 24 The second of the monochrome prints prepared in Example 22 is swabbed with a 2% solution of copper acetate in wate to form a copper-complexed magenta dye image of the photographed subject and exposed to heat and actinic radiation according to the procedure disclosed in Example 2.

The copper-complexed dye image exhibits substantially no degradation due to the heat and actinic radiation of the aforementioned procedure.

Example 25 A monochrome print is prepared according to the tolowing procedure.

A photosensitive element is prepared according to the procedure stated in Example 22. This photosensitive element is exposed and processed by spreading the liquid processing composition of Example 22 between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element comprises a cellulose acetate-coated baryta paper which has been coated with a solution comprising approximately 0.5% bis-(acetylacetono) copper (H) and 4% N-methoxymethyl polyhexamethylene adipamide in 80% aqueous isopropanol. After an imbibition period of approximately one minute, the image-receiving element is separated and contains a copper-complexed magenta dye image of the photographed subject.

The resultant print, containing the copper-complexed dye image, exhibits increased stability against the degradation effects of exposure to the heat and actinic radiation of the accelerated ageing test procedure disclosed in Example 2.

According to another embodiment of the present invention, monoand disazo dye developers containing hydroxyl and/or carboxyl radicals substituted, respectively, on aryl nuclei in position ortho to at least one azo linkage form stable coordination complexes as a result of contacting the appropriate dye developer with copper, nickel, cobalt, etc., ions and/ or chelates, preferably at a temperature in excess of room temperature.

The last-mentioned embodiment of the present invention will be illustrated in greater detail in conjunction with the following specific examples which set out representative utilizations of this embodiment which, however, are not limited to the details therein set forth and are intended to be illustrative only.

Example 26 A photosensitive element is prepared by coating a gelatin-coated film base with a solution containing 4% of 2-(4'-[fl-(hydroquinonyl) ethyl]-phenylazo)4-n-propoxy-naphthol, which is disclosed in the subsequently mentioned copending US. application Serial No. 612,045, in a 4% solution of cellulose acetate hydrogen phthalate in a 50:50 mixture, by volume, of acetone and tetrahydrofuran. After this coating has dried, a silver iodobromide emulsion is applied. This photosensitive emulsion is exposed and processed according to the procedure of Example 1. After an imbibition period of approximately one minute, the image-receiving element is separated and contains a magenta dye image of the photographed subject.

The image-receiving element is swabbed with an 0.5% solution of copper sulfate in a methanol-water solvent and maintained at a temperature of 80 C. for 1.5 hours to form a copper-complexed dye image of the photographed subject.

The copper-complexed dye image is exposed to heat and actinic radiation according to the procedure disclosed in Example 2. V

The purple copper-complexed dye image exhibits increased stability against the degradation effects of the heat and actinic radiation of the aforementioned procedure.

Example 27 An image-receiving element is prepared according to the procedure stated in Example 26. The image-receiving element is swabbed with an 0.5% solution of his- (acetylacetono) copper (II) in a water-methanol solvent, maintained at a temperature of 90 C. for 1.5 hours and then exposed to heat and actinic radiation according to the procedure disclosed in Example 2. p

The purple copper-complexed dye image exhibits increased stability against the degradation effects of the heat and actinic radiation of the aforementioned procedure. i

As examples of oitho-hydroxy and/or ortho,ortho-dihydroxy substituted monoand disazodyes preferred for use in the practice of the aforementioned embodiments of the present invention, mention may be made of the following:

2- (4'- [4"-(2"',5 "'-dihydroxyphenethyl -phenylazo] naphthalene azo )-4-1nethoxy-1-naphthol,

ll 2 p-'( 1-hydroxy-4-methoxy-2-naphthaleneazo) -.phenethyl catechol, 2- (pfl- (hydroquinonyl) -ethyl] -phenylazo -4-methoxy l-naphthol, 2- (p- ,H- (hydroquinonyl) -ethyl] phenylazo -4-npropoxyl-naphthol,

the preparations of which are disclosed in the copending US. application of Elkan R. Blout, Milton Green, and Howard G. Rogers, Serial No. 612,045, filed September 25, 1956; a

2- (2',5 '-dimethoxy-4- [p- (2",5 "-dihydroxyphenyl phenylazo] -phenylazo -4-methoxy-1-naphthol,

the preparation of which is disclosed in the copending US. application of Helen P. Husek and Myron S. Simon, Serial No. 612,054, filed September 25, 1956;

2- (2',5 '-clirnethoxy-4'- [p- (2",5"-dihydroxyphenethyl phenylazo] -ph'enylazo -4-methoxy-1-naphthol,

the preparation of which is disclosed in the copending U.S. application of Helen P. Husek, Serial No. 612,055, filed September 25, 1956;

2- p- [4'-methyl-2,5 dihydroxyphenylthioethyl phenylazo] -4-methoxy-1-naphthol,

the preparation of which is disclosed in the copending US. application of Milton Green and Howard G. Rogers, Serial No. 663,905, filed June 6, 1957;

2- (p- [2",5"-dihydroxyphenoxy] -phenylazo)-4-methoxyl-naphthol,

the preparation of which is disclosed in the 'copending US. application of Milton Green, Serial No. 680,403, filed August 26, 1957;

2- (p- [hydroquinonylsulfonyl] -phenylazo)-4-methoxyl-naphthol,

the preparation of which is disclosed in the copending US. application of Milton Green, Serial No. 680,434, filed August 26, 1957;

2-(2',5-dimethoxy-3- [2"-(2",5"'-dihydroxybenzoyl)- ethyl] -phenylazo -4-methoxy-1-naphthol,

the preparation of which is disclosed in the copending US. application of Elkan R. Blout, Milton Green, Howard G. Rogers, and Myron S. Simon, Serial No. 685,081, filed September 20, 1957;

2-(4'-[p-(hydroquinonyl)-phenylcarboxamido] phenylazo)-4-methoxy-1-naphthol,

the preparation of which is disclosed in the copending US. application of Milton Green, Serial No. 703,515, filed December 18, 1957;

G. Rogers, and Robert B. Woodward, Serial No. 707,109, filed January 6, 1958;

:2- 4' [4"- 2",5 "'-dihydroxyphenethyl -phenylcarb amyl] -phenylazo -4-methoxy-1-naphthol,

the preparation of which is disclosed in the copending US. application of Milton Green and Howard G. Rogers, Serial No. 748,145, filedJuly14, 1958;

2-hydroxynaphthaleneazohydroquinone,

which is disclosed in the aforementioned copending US. application, Serial No. 755,804; and

1- ('4- 2",5"-dihydroxyphenethyl] -2'-hydroxyphenylazo)-2-naphthol,

l3 the preparation of which is disclosed in the aforementioned copending US. application of Milton Green and Myron S. Simon, Serial No. 788,893, filed concurrently herewith.

According to still another embodiment of the present invention, dye developers such as monoazo, disazo and anthraquinone dye developers, characterized in that they contain preferably not less than one and not more than two o-dihydroxyphenyl groups or salicylic acid groups, may be stabilized against the color degradation effects of actinic radiation, humidity and/ or temperature variations by the formation of stable metallic coordination complexes by appropriate chelation of said o-dihydroxyphenyl groups or salicylic acid groups. The o-dihydroxyphenyl groups, which may be present as constituent components of the dye developer molecule to elfectuate, at least in part, development of a silver halide latent image, and/or the salicylic acid groups may be chelated, for example, by contacting said dye developer with an ionizable aluminum compound as, for example, an aluminum salt such as a nitrate, a sulfate, an oxalate, etc., in an ionized state, or an aluminum chelate, subsequent to transfer of image-forming dye developer to a superposed image-receiving element.

As examples of dye developers suitable for utilization in the last-mentioned embodiment of the present invention, mention may be made of:

NH-CzlL- 1,4-bis-(e- 3 ',4,-dihydroxyphenyl lethylamino) anthra quinone orn-oo-l r=nornonz on ii 0 H p-(3-methyl-l-phenyl-S-pyrazolone-i-azo)- phenethylcatechol The last-mentioned embodiment of the present invention will be illustrated in greater detail in conjunction with the following specific examples which set out a preferred utilization of this embodiment which, however, is not limited to the details therein set forth and is intended to be illustrative only.

l i- Example 28 A photosentitive element is prepared by coating a gelatin-coated film base with a solution containing 4% Z-naphthaleneazocatechol [Formula A], in a 4% solution of cellulose acetate hydrogen phthalate in a 50:50 mixture, by volume, of acetone and tetrahydrofuran. After this coating has dried, a silver iodobromide emulsion is applied. This photosensitive element is exposed and processed by spreading an aqueous liquid processing composition comprising:

- Percent Sodium carboxymethyl cellulose 4.5 p-Methylaminophenol 0.1 Sodium hydrom'de 2.0

between said photosensitive element and an image-receiving element as said elements are brought into superposed relationship. The image-receiving element comprises a cellulose acetate-coated baryta paper which has been coated with a solution comprising 0.5% aluminum nitrate and N-methoxymethyl polyhexamethylene adipamide in 95% ethanol. After an imbibition period of approximately one minute, the image-receiving element is separated and contains an orange dye image of the photographed subject.

Example 29 The product of Example 28, i.e., the image-receiving element containing the positive dye image of a photographed subject, is subjected to an accelerated ageing test by being heated to 90 C. in a relative humidity of for 12 hours. The position dye image definition remained sharply delimited.

Example 30 The procedure of Example 28, in which, however, the image-receiving element does not contain an aluminum salt constituent, is repeated and the uncomplexed positive dye image, a yellow image, is subjected to the procedure of Example 29. The positive dye image exhibited wandering and loss of image definition.

A still further embodiment of the present invention comprises forming stable metallic coordination complexes of anthraquinone dye developers. For example, anthraquinone dye developers substituted on at least one 0|:- position by hydroxyl groups may be suitably complexed by contact with a metallic ion or chelate according to the aforementioned procedures.

The preparations of anthraquinone dye developers having at least one a-hydroxy substituent are disclosed in the following copending U.S. applications:

Serial No. 478,922, filed December 30, 1954 in the names of Elkan R. Blout, Marilyn R. Cohler, Milton Green, Myron S. Simon and Robert B. Woodward;

Serial No. 485,342, filed January 31, 1955 in the name of Richard S. Corley; and

Serial No. 771,719 filed November 4, 1958 in the names of Elkan R. Blout and Richard S. Corley.

It will be recognized that an increase in the rate of transferred dye developer complexing, as well as the quantity of dye developer complexed, may be effected by increasing the temperature at which the complexing reaction takes place. For example, it has been determined that conducting the metal-complexing of ortho-hydroxyazo dye developers, according to the procedures illustrated in Examples 26 and 27, at an elevated temperature, provides decreased complexing time and dye images exhibiting increased concentration of metal-complexed dye.

It must be noted that metal complex-lug suitable dye developers provides a means of effecting a pronounced shift in the spectral absorption characteristics of the respective complexed dye developers. A means is thereby provided for effecting a desired spectral absorption curve shift, preferably a bathochromic shift, subsequent to photo-exposure of an associated silver halide emulsion, to provide increased emulsion speed in accordance with the disclosure contained in my copending US. application Serial No. 789,080, filed concurrently herewith.

While processes of the present invention have been described above, it is to be understood that these processes may be modified in many ways withoutdeparting from the scope of the invention. 7

It will be noted that the liquid processing composition may, and in the above examples does, contain an auxiliary or accelerating developer, such as metol, amidol,

benzylaminophenol, or a 3-pyrazolidone, such as l-phenyl-3-pyrazolidone. This auxiliary developer serves to accelerate and possibly initiatethe action of the dye developer. It is believed that some of the dye developer oxidized in exposed areas is oxidized by an energy transfer reaction with oxidized auxiliary developer.

The photographic dyes are preferably selected with a view to their usefulness in color photography and, in particular, their ability to provide, after complexing, the desired subtractive colors, i.e., magenta, yellow or cyan, in diffusion-transfer reversal processes utilizing color screen, bipack and tripack (monopack) photographic products.

It will be apparent that, by appropriate selection of the image-receiving element from among suitable known opaque and transparent materials,rit is possible to obtain either a colored positive reflection print or a colored positive transparency. Likewise, the inventive concepts herein set forth are adaptable for multicolor work by the use of special photographic materials, for example film materials of the type containing two or more photosensitized elements associated with an appropriate number of imagereceiving elements and adapted to be treated with one or more liquid processing compositions, appropriate dye developers suitable to provide the desired subtractive colors beingincorporated in the photosensitized elements or in the liquid processing compositions. Examples of such photographic materials are disclosed in US. Patent No. 2,647,049 to Edwin H. Land.

The inventive concepts herein set forth are also adaptable for the formation of stabilized colored images in accordance with the photographic products and processes described and claimed in the copending application of Edwin H. Land, Serial No. 448,441, filed August 9, 1954, and also the copending application of Edwin H. Land and Howard G. Rogers, Serial No. 565,135, filed February 13, 1956.

In the preceding portions of the specification the expression color has been frequently used. This expression is intended to include the use of a plurality of colors to obtain black, as well as the use of a single black dye developer.

Since certain changes may be made in the above products and processes without departing form the scope of the invention herein involved, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a process for forming a photographic image, the steps which comprise exposing a photosensitive element containing a silver halide emulsion; developing the exposed sllver halide emulsion in thepresence of an aqueous alkaline solution of a dye, which dye is a silver halide developing agent and contains a metalizable radical selected from the group consisting of and radicals;-oxidizing said dye in developed areas of said element, as a result of development, thereby providing immobilization of said dye, in developed areas of said element, as a function of the point-to-point degree of development thereof, and a predetermined distribution of mobile dye in the undeveloped areas of said element; transferring, by imbibition, at least a portion of said distribution from said undeveloped areas to an image-receiving element in superposed relationship with said element; contacting at least a portion of said transferred dye with metallic atoms selected from the group consisting of cobalt, nickel, copper and aluminum atoms; effecting thereby attachment of said atoms to the free valences of said metalizable radical to provide heterocyclic ring system formation, each of said ring systems comprising a metallic atom bonded to said -O group and one of said -U=N, OH and groups; and thereby providing to said irnage-receivingelement a reversed, at least in part, metal-complexed dye image of the developed image.

2. The process as defined in claim 1, wherein said metallic atoms are contained in said image-receiving element and the metal-complexeddye image is formed by permeating said element with said transferred dye.

3. The process as defined in claim 1, wherein said transfer-red dye is contacted with said metallic atoms at a temperature in excess of room temperature.

4. The process as defined in claim 1, wherein said metal-complexed dye image is formed by contacting the transferred dye containing image-receiving element, subsequent to disassociation of said element from its superposed relationship to said photosensitive element with a solution containing said metallic atoms.

5. In a process of forming a photographic image, the steps which comprise developing a latent image contained in an exposed silver halide emulsion in the presence of a dye, which dye is a silver halide developing agent, containing not less than one and not more than two orthohydroxyazo groups, oxidizing said dye in developed areas of said emulsion, as a result of development, providing thereby immobilization of said dye in the developed areas of said emulsion, as a function of the point-to-point degree of exposure thereof, providing in said emulsion a predetermined distribution of mobile dye, transferring at least part of said distribution, by imbibition, from said emulsion to an image-receiving element in superposed relationship with said emulsion and contacting at least part of said transferred dye with copper atoms in the presence of heat, complexing thereby at least part of said transferred dye, to impart to said image-receiving element a reversed, copper-complexed dye image of the latent image. 7

6. In a process of forming a photographic image, the steps which comprise developing a latent image contained in an exposed silver halide emulsion in the presence of a dye, which dye is a silver halide developing agent and contains not less than one and not more than two orthodihydroxyphenyl groups, oxidizing said dye in developed areas, as a result of development, thereby providing immobilization of said dye in the developed areas, as a function of the point-to-point degree of exposure thereof, thereby providing in said emulsion a predetermined distribution of mobile dye in the undeveloped areas thereof, transferring at least part of said distribution, by imbibit-ion, from said emulsion to an image-receiving element in superposed relationship with said emulsion and contacting at least part of said transferred dye with aluminum atoms, complexing therebyjat least part of said transferreddye, to impart to said image-receiving element a reversed; aluminum-complexed dye image of the developed image.

7. The process as defined in claim 6 wherein said aluminum atoms are derived from an ionized aluminum salt.

8. The process as defined in claim 7 wherein said aluminum salt is aluminum nitrate.

References Cited by the Examiner UNITED STATES PATENTS Ives 96-57 Brewster '9657 XR Roifo 9677 Alburger 96-57 Kvalnes et al 842 1 Graham.

Land 9676 XR Stark 96-57 XR Land.

Rogers 9629 Cohler et a1.

Straley et a1. 8-42 XR Corley.

Blout et a1.

Goulston et al.

FOREIGN PATENTS 554,212 7/57 Belgium. 554,935 8/57 Belgium.

5 OTHER REFERENCES Crossley: American Dyestuif Reporter, 27, Mar. 7, 1938, pp. 124-29.

Friedman: History of Color Photography, pages 481-484, American Photographic Publishing 0)., Boston 10 (1944).

Mees: The Theory of the Photographic Process, MacMillan, New York (1954), pp. 547-554.

Venkataraman: The Chemistry of Synthetic Dyes, vol. 1, Academic Press, New York (1952), pp. 270, 272 and 15 523-569.

W all: The History of Three-Color Photography, American Photo. Pub. Co., Boston (1925), pp. 390-398.

NORMAN G. TORCHIN, Primary Examiner.

20 MILTON STERMAN, PHILIP E. MANGAN, HAROLD N. BURSTEIN, ABRAHAM H. WINKELSTEIN,

Examiners. 

1. IN A PROCESS FOR FORMING A PHOTOGRAPHIC IMAGE, THE STEPS WHICH COMPRISE EXPOSING A PHOTOSENSITIVE ELEMENT CONTAINING A SILVER HALIDE EMULSION; DEVELOPING THE EXPOSED SILVER HALIDE EMULSION IN THE PRESENCE OF AN AQUEOUS ALKALINE SOLUTION OF A DYE, WHICH DYE IS A SILVER HALIDE DEVELOPING AGENT AND CONTAINS A METALIZABLE RADICAL SELECTED FROM THE GROUP CONSISTING OF 